IntroductionThe
consumer headphone market has evolved considerably over the last 30
years. Headphones have been used for better than a half-century as an
integral tool in the studio for recording and mastering due to their
accuracy and immediacy. As a teen, I owned a pair of higher-end
headphones that I used to defy my music curfew. They allowed me to
listen to my raucous music at concert volumes without disturbing or,
better yet, even alerting the rest of the household. Although the sonic
pureness of headphones has rarely been in question, the fact remains
that headphones, regardless of size, have always been plagued with the
reputation of being fatiguing to both wear and listen to for extended
periods of time. Additionally, there has been resistance from many
audiophiles, who place huge stock in soundstage accuracy and instrument
placement.

Sennheiser is no newcomer to the world of headphones.
In fact, most recognize Sennheiser as the world leader in headphone
transducer technology, as well as microphone, wireless and infrared
sound transmission. Founded back in June of 1945 in Wedemark, Germany,
following the end of WWII, Dr. Fritz Sennheiser and his team of
engineers embarked upon a journey that has led the company to the top
of their market.

The HD 650 is the flagship of Sennheiser’s consumer headphone line.
Retailing for $499, the HD 650s employ a dynamic speaker configuration
with an open shell design. The HD 650s have a frequency response of 10
Hz to 39,500 kHz. With headphones, the only statistic as important as
sound is comfort. The HD 650s weigh in at 260 grams or just over eight
ounces, making them an extremely light load for your neck to bear. The
HD 650s come with the standard 6.3mm jack, as well as a handy 3.5mm
adapter for smaller pieces, such as iPod and other portable devices.

The HD 650s come handsomely packaged in a silver hinging case that’s
nicely fitted with foam to protect your investment. Upon further
inspection, the HD 650s are a very sexy piece of gear. The outer
headphone is constructed with a high-gloss metal-flake plastic that
looks like a million bucks. On the external part of the earpiece are
matching gray, perforated screens that provide a view into the backside
of the speaker array. The speaker cups are oval in shape, measuring
four inches vertically and three inches across, and are fitted with a
soft, velvety fabric. An interesting feature: the cords have two-pin
connectors that plug into each of the ear cups. If you have a shorting
issue with the headphones, the cable can be easily replaced. Those who
use wired devices, such as headphones and game controllers, for
extended periods of time know that the cables can someday fail if they
are used excessively.

Headphone Fit
There are no two heads or two sets of ears that are the same.
Therefore, the best fit for headphones for you is determined the
old-fashioned way, by trying them on. There are a few basic
configurations for headphones. There is the common in-ear style, often
used with iPods or other portable devices. Then there is the over-ear
style that sit on top of the ear, and then the enclosed style like that
of the HD 650s. After using each of these on a regular basis, I offer
this assessment. In-ear is convenient for portable devices, but often
allows the majority of bass to escape, unless the earphones are fitted
with sealing earpieces. (This excludes the professional in-ear models
that are used by most touring musicians.) On-ear can often be the most
comfortable of the batch, but offers zero noise isolation and, again,
they allow bass information to escape. Enclosed headphones like the HD
650s offer a lower-noise experience, along with improved dynamics, due
to a more controlled inner environment.

Set-up
I utilized a variety of different sources to best evaluate the HD 650
headphones. My primary source was a Sonic Frontiers Line 3, outfitted
with Headroom headphone circuitry. This tube stage headphone amp has
been a reference of mine for many years. I additionally used the output
from my Kenwood DV-5900 and DR-5900 to test the HD 650s on a
moderately-priced source. Lastly, I used my iPod with MP3 files.

Music and Movies
It was suggested that the Sennheiser HD 650 headphones were not a good
match for lower-powered portable devices, such as my iPod, because they
could not produce adequate volume. I am happy to report that they were
wrong. The HD 650s provided as much or more volume than I can achieve
with the stock Apple headphones. They seem considerably louder, in
fact, due to the hugely increased bass response.

I started with Eric Clapton from his Unplugged CD (Reprise/WEA), using
my Apple iPod as a source. “Lonely Stranger” provided me with an
instant taste of what these headphones can do. There was major
improvement in the bass and overall tonal balance. As Clapton slowly
plucks his strings, the improved decay was greatly apparent.

One
side of me hesitates to recommend $500 headphones for use with a $250
player, yet it sounded fantastic. I switched to my Sonic Frontiers
setup and again listened to “Lonely Stranger.” Although I heard instant
improvement, it was clear that the HD 650s were making everything they
were plugged into sound great. There was solid isolation from the
outside world. I paused for a moment to notice the sounds of my
sprinklers running outside and TV playing in the upstairs room. Once
fitted with the HD 650s, there was almost complete silence. For those
with children – I was unable test this for you.

I
compared my reference system using my Revel Salon speakers, a system
that retails in the six figures, and noted that although the HD 650s
didn’t outperform the Revels with dynamics, in many ways they kept up.
They provided more immediacy and aural impact. Over the years,
headphones have gotten a bad rap. They have been used by many but never
fully respected in the audiophile world. True enthusiasts wouldn’t part
with their beloved soundstages and three-dimensional imaging that their
traditional speakers provided. Okay, so the HD 650s will not project
the images through your front wall. On the other hand, they did provide
a quality listening experience that you could only get with speakers
costing 10 to 20 times their price. Bass response was huge and they had
the knack for making instruments sound real.

Being fortunate enough to own one of Clapton’s signature Martins, I
proceeded to humbly play one of his tunes and felt that the Sennheisers
made the Martin tone most distinguishable: a great testament to
accuracy. I moved to the Kenwood set-up and, although my reference
system provided more information, the tone remained consistent with the
other sources tested.

I loaded up the newly released 10,000 Days CD from Tool (EMI/Virgin)
and played song nine, “Intension.” This cut starts with ambient noise
that falls somewhere between a soup kitchen and the jungle. Information
was clear and precise. There was very concise definition between
instruments and a sonic air that separated them nicely. The occasional
beat of a large kettledrum provided very low and accurate information.
My room has been measured down to 10 Hz and the HD 650s provided every
bit of low information. Of course, they lacked the physical impact of
my speakers, but they nevertheless provided the balance necessary to
experience a full-range listening experience. The bass guitar on this
cut was eerily solid and projected with good authority.

The Downside
Headphones
will not replace traditional speakers and, although they are the kings
of accuracy, they are not comfortable to listen to at high volumes for
extended periods of time. Some will find the HD 650s to be the most
comfortable pair of headphones they have ever worn. Others may not be
comfortable for long listening sessions. I fell in the middle. Although
they are the most comfortable enclosed headphones I have used, they
still cried to be removed after an hour or more of heavy listening.
This was largely due to my head shape. I have a narrow jaw and muscular
neck, so all headphones of this style tend to rest on my neck near my
tonsils. I circumvented this issue by adjusting the HD 650s to ride
higher on my head. This helped for longer listening sessions.

Conclusion
Although headphones have been part of my world for many years, they
have been primarily relegated to my portable devices for exercise. I
have a dedicated theater for listening and have no volume restrictions,
so why would I need headphones? Doing this review was an eye-opener.
Although the HD 650s won’t position a soundstage like traditional
speakers, they will provide dynamics that are only rivaled by
floor-standing speakers that cost as much as 10 times more. Bass was
solid and quick and provided me with a live music feeling. The midrange
was adequately sweet and liquid to made instruments sound very natural.
High frequencies were a real joy. Due to the fact they can often get
lost in an open room and cancelled by ambient noise, you will hear more
information than you have ever heard when listening through the
Sennheisers.

Headphones are no longer merely a tool for listening to music on the
down-low. The HD 650s are an easy way to get huge sound for just a
little bit of money. They are accurate, powerful and a necessary
accessory for every series music listener. Sennheiser got it seriously
right with their HD 650 headphones.